Name:Windows Files and Dirs Access Rights Modification Via Icacls id:c76b796c-27e1-4520-91c4-4a58695c749e version:4 date:2024-12-06 author:Teoderick Contreras, Splunk status:production type:TTP Description:The following analytic identifies the modification of security permissions on files or directories using tools like icacls.exe, cacls.exe, or xcacls.exe. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on specific command-line executions. This activity is significant as it is commonly used by Advanced Persistent Threats (APTs) and coinminer scripts to evade detection and maintain control over compromised systems. If confirmed malicious, this behavior could allow attackers to hinder investigation, impede remediation efforts, and maintain persistent access to the compromised environment. Data_source:
-Sysmon EventID 1
-Windows Event Log Security 4688
-CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly` min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name IN( "icacls.exe", "cacls.exe","xcacls.exe") AND Processes.process IN ("*:R*", "*:W*", "*:F*", "*:C*",, "*:N*","*/P*", "*/E*") by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_guid Processes.dest Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_files_and_dirs_access_rights_modification_via_icacls_filter`
how_to_implement:The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint` data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process. known_false_positives:Unknown. It is possible some administrative scripts use ICacls. Filter as needed. References: -https://malpedia.caad.fkie.fraunhofer.de/details/win.amadey drilldown_searches: name:'View the detection results for - "$dest$" and "$user$"' search:'%original_detection_search% | search dest = "$dest$" user = "$user$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$" and "$user$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Amadey' - 'Defense Evasion or Unauthorized Access Via SDDL Tampering' asset_type:Endpoint atomic_guid: - '3309f53e-b22b-4eb6-8fd2-a6cf58b355a9' confidence:70 impact:70 message:Process name $process_name$ with access right modification argument executed by $user$ to change security permission of a specific file or directory on host $dest$ mitre_attack_id: - 'T1222.001' - 'T1222' observable: name:'dest' type:'Endpoint' - role: - 'Victim' name:'user' type:'User' - role: - 'Victim' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' risk_score:49 required_fields: - '_time' - 'Processes.parent_process_name' - 'Processes.parent_process' - 'Processes.process_name' - 'Processes.process' - 'Processes.process_guid' - 'Processes.dest' - 'Processes.user' - 'Processes.process_id' - 'Processes.process' security_domain:endpoint
